SACRAMENTO - Zinfandel will flow like the water once did in Paso Robles this weekend. Bottles will pop open during a wine festival as rigs drill deep across the city to find a resource whose scarcity threatens Paso Robles to its core: water.

How scant has the crucial underground water supply become around the San Luis Obispo County city? Sue Luft can tell you anecdotally. The water levels in wells that feed homes and wineries around her 10-acre property just south of Paso Robles have dropped 80 feet in some areas, leaving many with no choice but to take out loans to drill farther down. Luft calls it a "race to the bottom."

Casting blame for depleting underground supplies is at the center of a bitter debate about who, if anyone, should be monitoring withdrawals.

Groundwater is loosely regulated in California, but that could change. Years of dry conditions have lawmakers looking at groundwater in ways once considered too politically risky.

In many areas across the state, property owners - who have a right to the water under their land - don't have to disclose how much they use from shared basins. Those who oppose groundwater regulation consider it government overreach.

"The drought is being used as a political mechanism to take away property rights," said Cindy Steinbeck of Steinbeck Vineyards & Winery in Paso Robles. "We are in a serious drought, but that doesn't mean individual landowners should have to give up what is theirs by law."

No regulation

Groundwater has been regulated in vastly different ways from other water sources. California requires permits and licenses to take water from streams, rivers and lakes, but no such process exists for groundwater. Surface water and groundwater are treated differently in state law in a way that resource experts say makes little sense, given that one affects the other.

"California has the least structure and fewest requirements (compared with any other) state," said Andrew Fahlund, deputy director of the California Water Foundation. "The system has survived up to this point because we weren't facing a significant crisis."

Eighty percent of Californians rely on groundwater for at least a portion of their drinking water, while some cities and rural areas exclusively use groundwater. The underground basins hold 10 times as much water as all the state's surface reservoirs combined.

The state's reliance on groundwater skyrockets during dry years and becomes critical during droughts.

"I like to think of groundwater as the state's water savings account," Fahlund said. "We are in a situation in many places where it's analogous to having overdrawn your savings account right before losing your job. We have this drought, and this is the time when you most need to rely on groundwater, but unfortunately our groundwater tables in many parts of the state have been overdrawn."

The California Water Foundation is spearheading a groundwater-management reform proposal that will be sent to the state Legislature and Gov. Jerry Brown. Throughout the state Capitol over the past six months, groundwater has been the subject of multiple hearings and meetings.

Brown has taken an increasingly serious tone in discussing groundwater management. In his budget proposal for 2014-15, he calls for spending $1.9 million on state intervention in cases where local and regional agencies "are unable or unwilling to sustainably manage groundwater basins."

"The water board will protect groundwater basins at risk of permanent damage until local or regional agencies are able to do so," Brown wrote in his budget proposal.

Funds for monitoring

He is also proposing $2.9 million for data collection and evaluation and $3 million for groundwater quality assessment. In February, Brown included $800,000 for overdraft management and $1 million for groundwater-level monitoring in emergency drought legislation that sailed through Sacramento.

"I think when people understand that our groundwater is disappearing and not coming back, acceptance for the need for careful monitoring is far more likely," said Jay Famiglietti, director of the UC Center for Hydrologic Modeling, while speaking at the California State Board of Food and Agriculture in November. "We are all focused on the surface water, and while no one is looking, we're pumping up the groundwater. I feel like no one is watching the groundwater, and it's running away."

Famiglietti said continuing to dig deeper is not sustainable. The deeper the well is, the worse the water quality becomes.

Luft smells the sulfur in her water and sighs. It didn't have to be this way.

Back in 2000, when she and her husband searched for the perfect place to begin a post-retirement career growing wine grapes, they looked for a sizable property with a good well. They made their home on Almond Drive.

"We did our due diligence when we bought the property," said Luft, who worked in an environmental engineering firm and was a co-manager of a small mutual water company. "We thought everything would be fine. Then we started tracking our water levels."

Despite their conservation lifestyle - from living in an eco-friendly straw-bale house to hand-tending their nearly dry-farmed grapes - the water levels kept falling. The rain needed to refill the 790-square-mile basin beneath the land was not enough to keep up with the growth of Paso Robles, where the acclaimed wine industry is critical to the area's $1.2 billion tourism economy.

"We just drew a new well two weeks ago," Luft said. "I'm watching a rig at a neighbor's place now. ... The problem is bad and progressively getting worse."

The water shortage created monumental rifts in the Paso Robles community, pitting winery versus winery, turning neighbors against neighbors over the best way to replenish the shared water basin. Three opposing groups formed to advocate for different approaches, from creating a water district to stopping future growth to adjudicating water rights through a court process.

Different philosophies

"We are kind of all peers, really," said Steinbeck, whose group hopes two lawsuits she's filed will force adjudication. "We just have very different philosophical arguments. Mine comes from a property-rights prospective and from (the idea that) if I take care of what I own and my neighbors do the same, we are the best stewards of this land."

But the fight over water has been ugly.

"People who were formerly friends became pretty brutal," Luft said.

Luft said she is amazed at how little California does to ensure that groundwater is used responsibly.

"Metering bothers a lot of people," she said. "It's like taking away guns when you say put a meter on a well. (But) reasonable people understand."